Sounds like a good deal, but watch out for the fine print (from one restaurant; not sure if all are the same):

Limit 1 redemption per party, per month, per restaurant
Limit 1 gift certificate per party, even if the party is seated at different tables and receives different checks
Valid for parties of 2 or more unless otherwise stated
Expires 1 year from date of issue
(Plus other miscellaneous terms)

Here's a special requirement at the one restaurant near me that participates:
Special Instructions: Valid with a minimum of 4 dinner entrees. Excludes alcohol.

So I have to order four entrees at probably $12-$15 each (a total of $48-$60) in order to redeem the $25 gift certificate. That's not a bad deal ($60 worth of food for $35...hope the T&C don't exclude taking stuff home in a doggie bag!), but it's definitely not like you're just getting free money, here.